Autonomous driving apparatus including a driving state switcher

ABSTRACT

A system includes an acquisition unit that acquires an operation amount or a duration count, and a switching unit that switches a driving state. The switching unit switches the driving state to the cooperative driving state when the operation amount is equal to or greater than an intervention threshold and less than a start threshold or the duration count is equal to or greater than a first threshold and less than a second threshold during the autonomous driving state, switches the driving state to the autonomous driving state when the operation amount is less than the intervention threshold or the duration count is less than the first threshold during the cooperative driving state, and switches the driving state to the manual driving state when the operation amount is equal to or greater than the start threshold or the duration count is equal to or greater than the second threshold.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.17/566,041, filed Dec. 30, 2021, which is a continuation of U.S.application Ser. No. 17/514,613 filed Oct. 29, 2021, which is acontinuation of U.S. application Ser. No. 16/845,260, filed Apr. 10,2020 (now U.S. Pat. No. 11,260,868 issued Mar. 1, 2022), which is acontinuation of U.S. application Ser. No. 15/805,544, filed Nov. 7, 2017(now U.S. Pat. No. 10,654,482 issued May 19, 2020), which is acontinuation of U.S. application Ser. No. 15/000,467, filed Jan. 19,2016 (now U.S. Pat. No. 9,845,096 issued Dec. 19, 2017), which claimsbenefit of priority of Japanese Patent Application No. 2015-008141,filed on Jan. 19, 2015. The entire disclosures of the prior applicationsincluding the specification, drawings and abstract are incorporatedherein by reference in their entirety.

BACKGROUND 1. Technical Field

The present disclosure relates to an autonomous driving vehicle system.

2. Description of Related Art

U.S. Pat. No. 8,527,199 describes a vehicle system which performsautonomous driving of a vehicle. The vehicle system controls the vehicleusing any one of an autonomous driving mode, a partial autonomousdriving mode, and a non-autonomous driving mode.

On the other hand, in the vehicle system of the related art, it isconsidered that a driver performs switching among the three modes usinga switch or the like. In this case, the driver operates the switch whenthe temporary intervention of the driver is required while the vehicleis controlled in the autonomous driving mode, and the driver needs tooperate the switch in switching from the partial autonomous driving modeor the non-autonomous driving mode to the autonomous driving mode afterthe intervention ends. For this reason, the driver may feel burdened.

SUMMARY

Exemplary aspects of the present disclosure provide an autonomousdriving vehicle system capable of reducing a burden given to a driverwhen the driver temporarily intervenes in a vehicle in an autonomousdriving state.

An autonomous driving vehicle system according to an aspect of thepresent disclosure includes a peripheral information detection unitconfigured to detect peripheral information of the vehicle; a travelingplan generation unit configured to generate a traveling plan along atarget route set in advance on a map based on the peripheral informationdetected by the peripheral information detection unit and mapinformation; a driving operation information acquisition unit configuredto acquire an operation amount of a driving operation of a driverrelating to at least one of a steering operation, an acceleratoroperation, and a brake operation of the vehicle or a duration countaccording to a duration of the driving operation; and a driving stateswitching unit configured to, based on the operation amount or theduration count, switch among an autonomous driving state where thetraveling of the vehicle is controlled using the traveling plan, acooperative driving state where the vehicle is allowed to travel incooperation with the driving operation based on the traveling plan andthe operation amount, and a manual driving state where the operationamount is reflected in the traveling of the vehicle. The driving stateswitching unit switches the driving state to the cooperative drivingstate when the driving state is the autonomous driving state and whenthe operation amount is equal to or greater than an interventiondetermination threshold value and less than a manual driving startthreshold value or the duration count is equal to or greater than afirst threshold value and less than a second threshold value, and whenthe driving state is the cooperative driving state, switches the drivingstate to the autonomous driving state when the operation amount is lessthan the intervention determination threshold value or the durationcount is less than the first threshold value, and switches the drivingstate to the manual driving state when the operation amount is equal toor greater than the manual driving start threshold value or the durationcount is equal to or greater than the second threshold value.

In the autonomous driving vehicle system according to the aspect of thepresent disclosure, the driving is switched to one of the autonomousdriving state, the manual driving state, and the cooperative drivingstate based on the operation amount of the driving operation or theduration count according to the duration of the driving operation. Forexample, when an oncoming vehicle of a heavy vehicle type appears duringtraveling in the autonomous driving state, the driver may perform adriving operation so as to travel at a position slightly distanced fromthe heavy vehicle. In this case, when the operation amount is equal toor greater than the intervention determination threshold value and lessthan the manual driving start threshold value or the duration count isequal to or greater than the first threshold value and less than thesecond threshold value, the driving state is switched to the cooperativedriving state by the driving state switching unit. When the driver stopsthe driving operation after having passed the oncoming vehicle, thedriving state is switched to the autonomous driving state by the drivingstate switching unit. For this reason, the autonomous driving vehiclesystem can reduce a burden given to the driver when the drivertemporarily intervenes in the vehicle in the autonomous driving state.

In the above-described aspect, when a steering wheel of the vehiclerotates according to a control target value of the steering wheelincluded in the traveling plan, the driving operation informationacquisition unit may acquire the difference between a rotation statedetection value of the steering wheel of the vehicle and the controltarget value of the steering wheel included in the traveling plan as anoperation amount of the steering operation. Alternatively, when a pedalposition of an accelerator pedal of the vehicle moves according to acontrol target value of the accelerator pedal included in the travelingplan, the driving operation information acquisition unit may acquire thedifference between a pedal position detection value of the acceleratorpedal of the vehicle and the control target value of the acceleratorpedal included in the traveling plan as an operation amount of theaccelerator operation. Alternatively, when a pedal position of a brakepedal of the vehicle moves according to a control target value of thebrake pedal included in the traveling plan, the driving operationinformation acquisition unit may acquire the difference between a pedalposition detection value of the brake pedal of the vehicle and thecontrol target value of the brake pedal included in the traveling planas an operation amount of the brake operation.

In this case, even when the steering wheel rotates according to thecontrol target value or the pedal position of the accelerator pedal orthe brake pedal moves, the driving operation information acquisitionunit can acquire the operation amount of the driver.

In the above-described aspect, when the driving state is the manualdriving state, the driving state switching unit may maintain the drivingstate in the manual driving state even when the operation amount is lessthan the manual driving start threshold value or the duration count isless than the second threshold value. In this case, the autonomousdriving vehicle system does not perform switching to the autonomousdriving state when the driver performs a driving operation in asufficient operation amount with the intention of continuing the manualdriving state or the driving operation is sufficiently continued;therefore, it is possible to reduce a burden in switching the drivingstate given to the driver who desires to continue the manual drivingstate.

In the above-described aspect, the autonomous driving vehicle system mayfurther include an input unit configured to input a request operation ofautonomous driving start of the driver, and the driving state switchingunit may maintain the driving state in the manual driving state untilthe request operation is input to the input unit when the driving stateis the manual driving state. In this case, the autonomous drivingvehicle system does not perform switching to the autonomous drivingstate until the driver requests to start autonomous driving; therefore,it is possible to reduce a burden in switching the driving state givento the driver who desires to continue the manual driving state.

In the above-described aspect, after the driving state of the vehicle isswitched from the autonomous driving state to the cooperative drivingstate, when the operation amount is less than the interventiondetermination threshold value but is equal to or greater than apredetermined threshold value, or the duration count is less than thefirst threshold value but is equal to or greater than a third thresholdvalue, the driving state switching unit may maintain the driving statein the cooperative driving state. In this case, the autonomous drivingvehicle system can avoid frequent switching of the driving state whenthe operation amount is substantially equal to the interventiondetermination threshold value or the duration count is substantiallyequal to the first threshold value.

In the above-described aspect, when the driving states corresponding tothe operation amounts of two or more of the steering operation, theaccelerator operation, and the brake operation of the vehicle aredifferent or the driving states corresponding to the duration counts oftwo or more of the steering operation, the accelerator operation, andthe brake operation of the vehicle are different, the driving stateswitching unit may give priority to maintaining the cooperative drivingstate over switching the driving state of the vehicle in the cooperativedriving state to the autonomous driving state, and may give priority toswitching to the manual driving state over maintaining the driving stateof the vehicle in the cooperative driving state.

In this case, for example, when the driver performs the steeringoperation and the accelerator operation, and when the driver performsthe steering operation with the intention of switching to the manualdriving state and performs the temporary accelerator operation, theautonomous driving vehicle system can avoid switching to the autonomousdriving state based on the release of the accelerator operation.

In the above-described aspect, when the driving state of the vehicle isthe cooperative driving state, cooperative driving may be performedusing a value obtained by weighting the operation amount and the controltarget value based on the traveling plan, and a weight of weighting whenthe operation amount is equal to or greater than a determinationthreshold value may be different from the weight of weighting when theoperation amount is less than the determination threshold value. In thiscase, the autonomous driving vehicle system can change the degree ofsystem intervention in the cooperative driving state.

According to the above-described aspect, it is possible to reduce aburden given to the driver when the driver temporarily intervenes in thevehicle in the autonomous driving state.

BRIEF DESCRIPTION OF THE DRAWINGS

Features, advantages, and technical and industrial significance ofexemplary embodiments of the present disclosure will be described belowwith reference to the accompanying drawings, in which like numeralsdenote like elements, and wherein:

FIG. 1 is a block diagram showing the configuration of an autonomousdriving vehicle system according to an embodiment;

FIG. 2 is a block diagram illustrating an ECU of FIG. 1 ;

FIG. 3 is a diagram illustrating an example of the relationship betweentorque of a steering operation and transition of a driving state of avehicle;

FIG. 4 is a flowchart illustrating an example of traveling plangeneration processing;

FIG. 5 is a flowchart illustrating an example of switching processingfor switching a driving state of a vehicle in a manual driving stateusing steering torque;

FIG. 6 is a flowchart illustrating an example of switching processingfor switching a driving state of a vehicle in an autonomous drivingstate or a cooperative driving state using steering torque;

FIG. 7A is a diagram illustrating an example of the relationship betweena duration count according to a steering operation and transition of adriving state;

FIG. 7B is a diagram illustrating an example of the relationship betweena duration count according to a steering operation and transition of adriving state;

FIG. 7C is a diagram illustrating an example of the relationship betweena duration count according to a steering operation and transition of adriving state;

FIG. 8A is a diagram illustrating another example of the relationshipbetween a duration count according to a steering operation andtransition of a driving state;

FIG. 8B is a diagram illustrating another example of the relationshipbetween a duration count according to a steering operation andtransition of a driving state;

FIG. 8C is a diagram illustrating another example of the relationshipbetween a duration count according to a steering operation andtransition of a driving state;

FIG. 9 is a flowchart illustrating an example of switching processingfor switching a driving state of a vehicle in a manual driving stateusing a duration count according to a steering operation;

FIG. 10 is a flowchart illustrating initial value setting processing;

FIG. 11 is a flowchart illustrating an example of switching processingfor switching a driving state of a vehicle in an autonomous drivingstate or a cooperative driving state using a duration count according toa steering operation;

FIG. 12A is a diagram illustrating an example of the relationship of asteering operation and a brake operation with transition of a drivingstate of a vehicle;

FIG. 12B is a diagram illustrating an example of the relationship of asteering operation and a brake operation with transition of a drivingstate of a vehicle;

FIG. 13 is a diagram illustrating another example of the relationshipbetween steering torque and transition of a driving state of a vehicle;and

FIG. 14 is a diagram illustrating an example of change of weighting in acooperative driving state.

DETAILED DESCRIPTION OF EMBODIMENTS

Hereinafter, exemplary embodiments of the present disclosure will bedescribed referring to the drawings. In the following description, thesame elements or corresponding elements are represented by the samereference numerals, and overlapping description will be omitted.

First Embodiment

FIG. 1 is a block diagram showing the configuration of an autonomousdriving vehicle system 100 according to a first embodiment. FIG. 2 is ablock diagram illustrating an electronic control unit (ECU) 10 in theautonomous driving vehicle system 100 of FIG. 1 . As shown in FIG. 1 ,the autonomous driving vehicle system 100 is mounted in a vehicle V,such as a passenger car. The autonomous driving vehicle system 100includes an external sensor (peripheral information detection unit) 1, aglobal positioning system (GPS) reception unit 2, an internal sensor 3,a map database 4, a navigation system 5, an actuator 6, a human machineinterface (HMI) 7, and an ECU 10.

The external sensor 1 is a device which detects an external situation asperipheral information of the vehicle V. The external sensor 1 includesat least one of a camera, a radar, and a laser imaging detection andranging (LIDAR).

The camera is a device which images the external situation of thevehicle V. The camera is provided, for example, in the inside of awindshield of the vehicle V. The camera may be a monocular camera or astereo camera. The stereo camera has, for example, two imaging unitswhich are arranged so as to reproduce binocular parallax. Imaginginformation of the stereo camera includes, for example, information of adepth direction. The camera outputs imaging information relating to theexternal situation of the vehicle V to the ECU 10. The camera may havetwo or more imaging units.

The radar detects an object outside the vehicle V using an electric wave(for example a radio wave). An electric wave is, for example, amillimeter wave. The radar transmits an electric wave to the peripheryof the vehicle V and receives an electric wave reflected by the objectto detect the object. The radar can output, for example, the distance ordirection to the object as object information. The radar outputs thedetected object information to the ECU 10. When sensor fusion (a methodof integrally processing a plurality of kinds of sensor information toimprove detection accuracy) is performed at a subsequent stage,reception information of the reflected electric wave may be output tothe ECU 10.

The LIDAR detects an object outside the vehicle V using light. The LIDARtransmits light to the periphery of the vehicle V and receives lightreflected by the object to measure the distance to the reflection pointand to detect the object. The LIDAR can output, for example, thedistance or direction to the object as object information. The LIDARoutputs the detected object information to the ECU 10. When sensorfusion is performed at a subsequent stage, reception information ofreflected light may be output to the ECU 10. The external sensor 1 isnot necessarily provided with a plurality of cameras, radars, or LIDARs.

The GPS reception unit 2 receives signals from three or more GPSsatellites to acquire positional information indicating the position ofthe vehicle V. The positional information includes, for example, alatitude and a longitude. The GPS reception unit 2 outputs the measuredpositional information of the vehicle V to the ECU 10. Instead of theGPS reception unit 2, other means capable of specifying the latitude andlongitude of the vehicle V may be used.

The internal sensor 3 is a detector which detects information accordingto a traveling state of the vehicle V and information (driving operationinformation) according to a driving operation of the driver of thevehicle V. The internal sensor 3 includes at least one of a vehiclespeed sensor, an acceleration sensor, and a yaw rate sensor in order todetect information according to the traveling state of the vehicle V.Furthermore, the internal sensor 3 includes at least one of anaccelerator pedal sensor, a brake pedal sensor, and a steering sensor inorder to detect driving operation information.

The vehicle speed sensor is a detector which detects the speed of thevehicle V. As the vehicle speed sensor, for example, a wheel speedsensor which is provided in a wheel of the vehicle V or a drive shaftrotating integrally with the wheel and detects the rotation speed of thewheel is used. The vehicle speed sensor outputs vehicle speedinformation (wheel speed information) including the speed of the vehicleV to the ECU 10.

The acceleration sensor is a detector which detects the acceleration ofthe vehicle V. The acceleration sensor includes, for example, alongitudinal acceleration sensor which detects the longitudinalacceleration of the vehicle V, and a lateral acceleration sensor whichdetects the lateral acceleration of the vehicle V. The accelerationsensor outputs acceleration information including the acceleration ofthe vehicle V to the ECU 10.

The yaw rate sensor is a detector which detects a yaw rate (rotationangular velocity) around a vertical axis of the center of gravity of thevehicle V. As the yaw rate sensor, for example, a gyro sensor can beused. The yaw rate sensor outputs yaw rate information including the yawrate of the vehicle V to the ECU 10.

The accelerator pedal sensor is, for example, a detector which detectsthe depression amount of the accelerator pedal. The depression amount ofthe accelerator pedal is the position (pedal position) of theaccelerator pedal based on a predetermined position. The predeterminedposition may be a fixed position or may be a position changed by apredetermined parameter. The accelerator pedal sensor is provided in,for example, a shaft portion of the accelerator pedal of the vehicle V.The accelerator pedal sensor outputs operation information according tothe depression amount of the accelerator pedal to the ECU 10. When thepedal position of the accelerator pedal moves according to a controltarget value of the accelerator pedal included in a traveling plandescribed below, the accelerator pedal sensor detects a pedal positionin which both the accelerator pedal operation and the system controlinput are reflected. When the pedal position of the accelerator pedaldoes not move according to a control target value of the acceleratorpedal included in a traveling plan described below, the acceleratorpedal sensor detects a pedal position according to the accelerator pedaloperation.

The brake pedal sensor is, for example, a detector which detects thedepression amount of the brake pedal. The depression amount of the brakepedal is, for example, the position (pedal position) of the brake pedalbased on a predetermined position. The predetermined position may be afixed position or may be a position changed by a predeterminedparameter. The brake pedal sensor is provided in, for example, a portionof a brake pedal. The brake pedal sensor may detect the operation force(the depression force to the brake pedal, the pressure of a mastercylinder, or the like) of the brake pedal. The brake pedal sensoroutputs operation information according to the depression amount oroperation force of the brake pedal to the ECU 10. When the pedalposition of the brake pedal moves according to a control target value ofthe brake pedal included in a traveling plan described below, the brakepedal sensor detects a pedal position in which both the brake pedaloperation and the system control input are reflected. When the pedalposition of the brake pedal does not move according to a control targetvalue of the brake pedal included in a traveling plan described below,the brake pedal sensor detects a pedal position according to a brakepedal operation.

The steering sensor is, for example, a detector which detects therotation state of the steering wheel. A detection value of the rotationstate is, for example, steering torque or a steering angle. The steeringsensor is provided in, for example a steering shaft of the vehicle V.The steering sensor outputs information including steering torque or thesteering angle of the steering wheel to the ECU 10. When the steeringwheel rotates according to a control target value of the steering wheelincluded in a traveling plan described below, the steering sensordetects steering torque or a steering angle in which both the steeringoperation and the system control input are reflected. When the steeringwheel does not rotate according to a control target value of thesteering wheel included in a traveling plan described below, thesteering sensor detects steering torque or a steering angle according tothe steering operation.

The map database 4 is a database which includes map information. The mapdatabase 4 may be formed in, for example, a hard disk drive (HDD)mounted in the vehicle V. The map information includes, for example,positional information of roads, information of road shapes, andpositional information of intersections and junctions. Information ofroad shapes includes, for example, classifications of curves andstraight portions, curvatures of curves, and the like. Furthermore, whenthe autonomous driving vehicle system 100 uses positional information ofshield structures, such as buildings or walls, or a simultaneouslocalization and mapping (SLAM) technique, an output signal of theexternal sensor 1 may be included in the map information. The mapdatabase 4 may be stored in a computer of a facility, such as aninformation processing center communicable with the vehicle V.

The navigation system 5 is a device which performs guidance to adestination set on a map by the driver of the vehicle V for the driverof the vehicle V. The navigation system 5 calculates a traveling routeof the vehicle V based on the positional information of the vehicle Vmeasured by the GPS reception unit 2 and the map information of the mapdatabase 4. The route may be, for example, a route where a travelinglane of the vehicle V is specified in a multi-lane section. Thenavigation system 5 calculates, for example, a target route from theposition of the vehicle V to the destination, and notifies the driver ofthe target route by the display on a display and speech output of aspeaker. The navigation system 5 outputs, for example, information ofthe target route of the vehicle V to the ECU 10. The navigation system 5may use information stored in a computer of a facility, such as aninformation processing center communicable with the vehicle V.Alternatively, part of the processing performed by the navigation system5 may be performed by the computer of the facility.

The actuator 6 is a device which executes traveling control of thevehicle V. The actuator 6 includes at least a throttle actuator, a brakeactuator, and a steering actuator. The throttle actuator controls thesupply amount (throttle opening) of air to an engine according to acontrol signal from the ECU 10 and controls a drive force of the vehicleV. When the vehicle V is a hybrid vehicle or an electric vehicle, thethrottle actuator is not included, and a control signal from the ECU 10is input to a motor as a power source and the drive force is controlled.

The brake actuator controls a brake system according to a control signalfrom the ECU 10 and controls a drive force provided to the wheel of thevehicle V. As the brake system, for example, a hydraulic brake systemcan be used. The steering actuator controls the driving of an assistmotor controlling steering torque in an electric power steering systemaccording to a control signal from the ECU 10. With this, the steeringactuator controls steering torque of the vehicle V.

The HMI 7 is an interface for output and input of information between anoccupant (including the driver) of the vehicle V and the autonomousdriving vehicle system 100. The HMI 7 includes, for example, a displaypanel for displaying image information to the occupant, a speaker forspeech output, and operation buttons or a touch panel for an inputoperation of the occupant. As shown in FIG. 2 , the HMI 7 includes anautonomous driving ON/OFF switch 70 which is an input unit configured toinput a start request operation of autonomous driving start by theoccupant. The autonomous driving ON/OFF switch 70 may be configured suchthat an end request operation relating to autonomous driving end can beinput by the occupant. If a request operation relating to autonomousdriving start or end is performed by the occupant, the autonomousdriving ON/OFF switch 70 outputs information indicating autonomousdriving start or autonomous driving end to the ECU 10. The input unit isnot limited to a switch, and any input unit may be used as long asinformation determining the driver's intention of autonomous drivingstart or end can be input. For example, the input unit may be anautonomous driving start button and an autonomous driving end button, ormay be objects of switches or buttons displayed on a screen operable bythe driver. When the vehicle arrives at the destination where autonomousdriving ends, the HMI 7 notifies the occupant of arrival at thedestination. The HMI 7 may output information to the occupant using aportable information terminal connected in a wireless manner or mayreceive an input operation of the occupant using the portableinformation terminal. Furthermore, the HMI 7 may output a notificationto the occupant indicating which of three states of an autonomousdriving state, a cooperative driving state, and a manual driving statethe vehicle is currently in.

The ECU 10 shown in FIGS. 1 and 2 controls autonomous traveling of thevehicle V. The ECU 10 is an electronic control unit having a centralprocessing unit (CPU), a read only memory (ROM), a random access memory(RAM), and the like. The ECU 10 loads programs stored in the ROM to theRAM and executes the programs on the CPU, thereby executing variouskinds of control. The ECU 10 may be constituted of a plurality ofelectronic control units.

As shown in FIGS. 1 and 2 , the ECU 10 includes a vehicle positionrecognition unit 11, an external situation recognition unit 12, atraveling state recognition unit 13, a traveling plan generation unit14, a driving operation information acquisition unit 15, a driving stateswitching unit 16, and a traveling control unit 17.

The vehicle position recognition unit 11 recognizes the position(hereinafter, referred to as “vehicle position”) of the vehicle V on themap based on the positional information of the vehicle V received by theGPS reception unit 2 and the map information of the map database 4. Thevehicle position recognition unit 11 may acquire and recognize thevehicle position used in the navigation system 5 from the navigationsystem 5. When the vehicle position of the vehicle V can be measured bya sensor provided on the outside, such as a road, the vehicle positionrecognition unit 11 may acquire the vehicle position from the sensor bycommunication.

The external situation recognition unit 12 recognizes the externalsituation of the vehicle V based on the detection result of the externalsensor 1. The detection result includes, for example, the imaginginformation of the camera, the object information of the radar, theobject information of the LIDAR, or the like. The external situation mayinclude, for example, the position of a white line or the position ofthe lane center of a traveling lane of the vehicle V and a road width,and a shape of a road. A shape of a road may be, for example, acurvature of a traveling lane, a change in gradient of a road surfaceeffective for prospective estimation of the external sensor 1,undulation, or the like. The external situation may be a situation of anobject, such as an obstacle in the periphery of the vehicle V. Asituation of an object includes, for example, information fordistinguishing between a fixed obstacle and a moving obstacle, theposition of an obstacle with respect to the vehicle V, a movingdirection of an obstacle with respect to the vehicle V, a relative speedof an obstacle with respect to the vehicle V, or the like. The externalsituation recognition unit 12 may compare the detection result of theexternal sensor 1 with the map information and may correct the positionand direction of the vehicle V acquired by the GPS reception unit 2 orthe like to increase accuracy.

The traveling state recognition unit 13 recognizes the traveling stateof the vehicle V based on the detection result of the internal sensor 3.The detection result of the internal sensor 3 includes, for example, thevehicle speed information of the vehicle speed sensor, the accelerationinformation of the acceleration sensor, the yaw rate information of theyaw rate sensor, and the like. Information indicating the travelingstate of the vehicle V includes, for example, a vehicle speed, anacceleration, or a yaw rate.

The traveling plan generation unit 14 generates a route of the vehicle Vbased on, for example, the target route calculated by the navigationsystem 5, the vehicle position recognized by the vehicle positionrecognition unit 11, and the external situation (including the vehicleposition and direction) of the vehicle V recognized by the externalsituation recognition unit 12. The route is a traveling locus of thevehicle V in the target route. The traveling plan generation unit 14generates the route such that the vehicle V travels on the target routewhile satisfying the standards, such as safety, compliance, andtraveling efficiency. Furthermore, the traveling plan generation unit 14generates the route of the vehicle V so as to avoid contact with anobject based on the situation of an object in the periphery of thevehicle V.

The target route described in this specification includes a travelingroute which is automatically generated based on the external situationor the map information when setting of a destination is not explicitlyperformed by the driver, like a road traveling route in a “drivingassistance device described in Japanese Patent No. 5382218(WO2011/158347) or an “autonomous driving device” described in JapanesePatent Application Publication No. 2011-162132.

The traveling plan generation unit 14 generates a traveling planaccording to the generated route. That is, the traveling plan generationunit 14 generates a traveling plan according to the target route set inadvance on the map based on at least one of the external situation asthe peripheral information of the vehicle V and the map information ofthe map database 4. The traveling plan generation unit 14 generates atraveling plan including a plurality of sets having two elements, thetwo elements comprising a target position p in a coordinate system fixedto the vehicle V indicating the route of the vehicle V, and a targetspeed v at the target position. That is, the traveling plan generationunit 14 may generate a traveling plan including a plurality ofconfiguration coordinates (p, v). Each of a plurality of targetpositions p has at least the position of the x coordinate or the ycoordinate in a coordinate system fixed to the vehicle V, or informationequivalent to the position of the x coordinate or the y coordinate. Thetraveling plan may include information indicating the behavior of thevehicle V, and is not limited to a plan including the configurationcoordinates. For example, the traveling plan may include a target timet, instead of the target speed v, as information indicating the behaviorof the vehicle V, or may include the target time t and informationrelating to the direction of the vehicle V at this time.

In general, the traveling plan is sufficient with data indicating a planfrom the current time to the future by several seconds ahead. However,there is a case where data indicating a plan up to tens of seconds aheadis required depending on a situation, such as a right turn at anintersection or passing of the vehicle V. Assuming this case, the numberof configuration coordinates of the traveling plan may be variable, andthe distance between the configuration coordinates may be variable.Furthermore, a curve connecting adjacent configuration coordinates maybe approximated using a spline function or the like, and the parametersof the approximated curve may be set as a traveling plan. A method ofgenerating a traveling plan may represent the behavior of the vehicle V,and an arbitrary well known method can be employed, for example.

The traveling plan includes, for example, a target control value whenthe autonomous driving vehicle system 100 performs vehicle control. Forexample, the traveling plan may be set as data indicating changes in thevehicle speed of the vehicle V, the acceleration/deceleration, steeringtorque of the steering wheel, and the like when the vehicle V travelsalong the route following the target route. That is, the traveling planmay include a speed pattern of the vehicle V, anacceleration/deceleration pattern, and a steering torque pattern.Alternatively, the traveling plan may be set as data indicating changesin the control target value of the accelerator pedal and the controltarget value of the brake pedal, instead of the speed pattern of thevehicle V and the acceleration/deceleration pattern. The traveling plangeneration unit 14 may generate a traveling plan such that a travel time(a required time until the vehicle V arrives at the destination) is theshortest.

The speed pattern is, for example, data having a target vehicle speedset in association with the time for each target control position withrespect to target control positions set at a predetermined interval (forexample, 1 m) on a route. The acceleration/deceleration pattern is, forexample, data having a target acceleration/deceleration set inassociation with the time for each target control position with respectto target control positions set at a predetermined interval (forexample, 1 m) on a route. The steering pattern is, for example, datahaving target steering torque set in association with the time for eachtarget control position with respect to target control positions set ata predetermined interval (for example, 1 m) on a route. Data indicatingchanges in the control target value of the accelerator pedal and thecontrol target value of the brake pedal is, for example, data having thepedal position set in association with the time for each target controlposition with respect to target control positions set at a predeterminedinterval (for example, 1 m) on a route.

For example, when information indicating autonomous driving start isacquired from the autonomous driving ON/OFF switch 70, the travelingplan generation unit 14 generates a traveling plan. The traveling plangeneration unit 14 outputs the generated traveling plan to the drivingoperation information acquisition unit 15 and the traveling control unit17. When the driving operation information acquisition unit 15 does notneed to use the traveling plan, for example, as described below, whenthe state of the driving operation can be acquired only using thedetection value of the internal sensor 3, the traveling plan generationunit 14 may not output the traveling plan to the driving operationinformation acquisition unit 15.

The driving operation information acquisition unit 15 acquires drivingoperation information, which is information according to the drivingoperation of the driver, based on the detection result of the internalsensor 3. For example, the driving operation information acquisitionunit 15 acquires the operation amount of the driving operation relatingto at least one of the steering operation, the accelerator operation,and the brake operation of the vehicle V as the driving operationinformation. The steering operation is, for example, the rotationoperation of the steering wheel by the driver. That is, the drivingoperation information relating to the steering operation includes theoperation amount (steering torque or steering angle) of the steeringwheel. When the steering wheel of the vehicle V rotates according to thecontrol target value (target steering torque) of the steering wheelincluded in the traveling plan, the driving operation informationacquisition unit 15 acquires the difference between a rotation statedetection value of the steering wheel of the vehicle V detected by thesteering sensor and the control target value of the steering wheelincluded in the traveling plan generated by the traveling plangeneration unit 14 as the operation amount of the steering operation.Since it should suffice that deviation from the control target value canbe detected, for example, the difference between a differential value ofthe rotation state detection value and a differential value of thecontrol target value may be used. When the steering wheel does notrotate according to the control target value of the steering wheelincluded in the traveling plan, the driving operation informationacquisition unit 15 acquires the rotation state detection value of thesteering wheel of the vehicle V detected by the steering sensor as theoperation amount of the steering operation. In any case, the drivingoperation information acquisition unit 15 may acquire the absolute valueof the operation amount of the driver. The accelerator operation is, forexample, the depression operation of the accelerator pedal by thedriver. That is, driving operation information relating to theaccelerator operation includes information according to the operationamount (depression amount) of the accelerator pedal. The brake operationis, for example, the depression operation of the brake pedal by thedriver. That is, driving operation information relating to the brakepedal operation includes information according to the operation amount(depression amount) of the brake pedal. In regard to the acceleratoroperation and the brake operation, similar to the steering operationdescribed above, when the pedal position is changed according to asystem control value, the difference between the detection value and thecontrol target value is calculated and the absolute value of theoperation amount of the driver is acquired. That is, when the pedalposition of the accelerator pedal of the vehicle V moves according tothe control target value of the accelerator pedal included in thetraveling plan, the driving operation information acquisition unit 15acquires the difference between the pedal position detection value ofthe accelerator pedal of the vehicle V and the control target value ofthe accelerator pedal included in the traveling plan as the operationamount of the accelerator operation. The control target value of theaccelerator pedal may be derived from the vehicle speed of the vehicleV, the acceleration/deceleration, or the like included in the travelingplan. Similarly, when the pedal position of the brake pedal of thevehicle V moves according to the control target value of the brake pedalincluded in the traveling plan, the driving operation informationacquisition unit 15 acquires the difference between the pedal positiondetection value of the brake pedal of the vehicle V and the controltarget value of the brake pedal included in the traveling plan as theoperation amount of the brake operation. The control target value of thebrake pedal may be derived from the vehicle speed of the vehicle V, theacceleration/deceleration, or the like included in the traveling plan.The driving operation information acquisition unit 15 outputs thedriving operation information to the driving state switching unit 16 andthe traveling control unit 17.

The driving state switching unit 16 switches the driving state of thevehicle V based on the driving operation information acquired by thedriving operation information acquisition unit 15. Hereinafter, a casewhere the driving state switching unit 16 switches the driving state ofthe vehicle V based on the operation amount of the steering operation asan example of the driving operation will be described.

FIG. 3 is a diagram illustrating an example of the relationship betweenthe operation amount of the steering operation and transition of thedriving state of the vehicle V. FIG. 3 shows a case where the operationamount of the steering operation is the steering torque as an example.The horizontal axis of FIG. 3 represents steering torque [T], and thevertical axis represents a driving state. As shown in FIG. 3 , thedriving state of the vehicle V includes three states of an autonomousdriving state, a cooperative driving state, and a manual driving state.

The autonomous driving state is, for example, a state where traveling ofthe vehicle V is controlled using the traveling plan. That is, theautonomous driving state is, for example, a state where the driver doesnot perform the steering operation and traveling of the vehicle V isrealized only by the control of the autonomous driving vehicle system100 in a state where there is no intervention of the driver. Thecooperative driving state is, for example, a driving state where thevehicle V is allowed to travel in cooperation with the steeringoperation based on the traveling plan and the operation amount of thesteering operation. That is, the cooperative driving state is a statewhere both the driver and the autonomous driving vehicle system 100 canbe involved in traveling of the vehicle V and a state where traveling ofthe vehicle V is realized based on at least the operation amount of thesteering operation of the driver in a state where system intervention ispossible. The manual driving state is a state where the operation amountof the steering operation of the driver is reflected in traveling of thevehicle V. That is, the manual driving state is a state where theoperation amount of the steering operation of the driver is reflected intraveling of the vehicle V in a state where system intervention is notpossible.

The driving state switching unit 16 switches among the autonomousdriving state, the cooperative driving state, and the manual drivingstate based on steering torque according to the steering operation. Whensteering torque according to the steering operation is less than anintervention determination threshold value T₁, the driving state of thevehicle V becomes the autonomous driving state. The interventiondetermination threshold value T₁ is a value set in advance, and athreshold value for determining the presence or absence of operationintervention of the driver. In the first embodiment, the interventiondetermination threshold value T₁ is a threshold value which is used inorder to determine switching from the autonomous driving state to thecooperative driving state. When steering torque according to thesteering operation is equal to or greater than the interventiondetermination threshold value T₁ and less than a manual driving startthreshold value T₂, the driving state of the vehicle V becomes thecooperative driving state. The manual driving start threshold value T₂is a value set in advance, and a threshold value for determiningswitching from the cooperative driving state to the manual drivingstate. When steering torque according to the steering operation is equalto or greater than the manual driving start threshold value T₂, thedriving state of the vehicle V becomes the manual driving state.

Next, the determination (maintenance or transition) of the driving stateof the vehicle V will be described. First, the maintenance or transitionof the autonomous driving state will be described. The driving stateswitching unit 16 maintains the driving state of the vehicle V in theautonomous driving state when the driving state of the vehicle V is theautonomous driving state and when steering torque according to thesteering operation is less than the intervention determination thresholdvalue T₁. With this, for example, even when a steering operation notintending the release of autonomous driving is detected, for example,even when the driver touches the steering wheel unintentionally, or thelike, the autonomous driving state is not released. For this reason, thedriving state switching unit 16 can avoid the operation of theautonomous driving ON/OFF switch 70 of the driver in order to instructautonomous driving start each time the driver releases autonomousdriving unintentionally; therefore, it is possible to reduce a burdengiven to the driver.

The driving state switching unit 16 switches the driving state of thevehicle V to the cooperative driving state when the driving state of thevehicle V is the autonomous driving state and when steering torqueaccording to the steering operation is equal to or greater than theintervention determination threshold value T₁ and less than the manualdriving start threshold value T₂. With this, for example, when thedriver operates the steering wheel in an operation amount equal to orgreater than the intervention determination threshold value T₁ and lessthan the manual driving start threshold value T₂ in order to intervenein the vehicle in the autonomous driving state, the driving state of thevehicle V transitions from the autonomous driving state to thecooperative driving state. For example, when an oncoming vehicle of aheavy vehicle type appears during traveling in the autonomous drivingstate, and when the driver performs a steering operation so as totemporarily travel at a position slightly distanced from the heavyvehicle, the driving state of the vehicle V is switched to thecooperative driving state by the driving state switching unit 16. Inthis case, since the vehicle V travels based on the steering operationof the driver in a state where system intervention is possible, theautonomous driving vehicle system 100 can allow the vehicle V to travelat a position based on the steering operation of the driver.

The driving state switching unit 16 may switch the driving state of thevehicle V to the manual driving state when the driving state of thevehicle V is the autonomous driving state and when steering torqueaccording to the steering operation is equal to or greater than themanual driving start threshold value T₂. That is, the driving state ofthe vehicle V may directly transition from the autonomous driving stateto the manual driving state without passing through the cooperativedriving state.

Next, the maintenance or transition of the cooperative driving statewill be described. The driving state switching unit 16 switches thedriving state of the vehicle V from the cooperative driving state to theautonomous driving state when the driving state of the vehicle V is thecooperative driving state and when steering torque according to thesteering operation is less than the intervention determination thresholdvalue T₁. With this, for example, when the driver performs the steeringoperation such that the vehicle V travels at a position slightlydistanced from a heavy vehicle as an oncoming vehicle and the driverstops the steering operation after having passed the oncoming vehicle,the driving state of the vehicle V is switched from the cooperativedriving state to the autonomous driving state by the driving stateswitching unit 16. In this way, when operation intervention istemporary, the driving state is automatically switched to the autonomousdriving state based on steering torque according to the steeringoperation. Therefore, since the driving state switching unit 16 canavoid having the driver operate the autonomous driving ON/OFF switch 70in order to instruct autonomous driving start each time temporaryautonomous driving is released, it is possible to reduce a burden givento the driver.

The driving state switching unit 16 maintains the cooperative drivingstate when the driving state of the vehicle V is the cooperative drivingstate and when steering torque according to the steering operation ismaintained equal to or greater than the intervention determinationthreshold value T₁ and less than the manual driving start thresholdvalue T₂. At this time, the total operation amount of the control targetvalue based on the traveling plan and the operation amount of the drivermay be reflected in traveling of the vehicle V, or the total operationamount of an operation amount smaller than the control target valuebased on the traveling plan and the operation amount of the driver maybe reflected in traveling of the vehicle V. The operation amount smallerthan the control target value based on the traveling plan includes 0.When the operation amount smaller than the control target value based onthe traveling plan is 0, steering torque according to the steeringoperation of the driver is reflected in traveling of the vehicle V in astate where system intervention is possible. The driving state switchingunit 16 switches the driving state of the vehicle V from the cooperativedriving state to the manual driving state when the driving state of thevehicle V is the cooperative driving state and when steering torqueaccording to the steering operation is equal to or greater than themanual driving start threshold value T₂. With this, steering torqueaccording to the steering operation of the driver is reflected intraveling of the vehicle V in a state where system intervention is notpossible.

Next, the maintenance or transition of the manual driving state will bedescribed. When the driving state of the vehicle V is the manual drivingstate, the driving state switching unit 16 maintains the driving stateof the vehicle V in the manual driving state even when steering torqueaccording to the steering operation becomes less than the manual drivingstart threshold value T₂. In this case, when the driver performs thesteering operation in a sufficient operation amount with the intentionof continuing the manual driving state, switching to the autonomousdriving state or the cooperative driving state is limited subsequently,for example switching to the autonomous driving state or the cooperativedriving state is prohibited or restricted; therefore, it is possible toeliminate the need for the driver to operate the autonomous drivingON/OFF switch 70 in order to instruct autonomous driving end. For thisreason, it is possible to reduce a burden given to the driver.

The driving state switching unit 16 maintains the manual driving stateuntil the request operation of autonomous driving start is input to theautonomous driving ON/OFF switch 70 when the driving state of thevehicle V is the manual driving state. That is, even when steeringtorque becomes less than the manual driving start threshold value T₂,switching to the cooperative driving state or the autonomous drivingstate is limited until the request operation of autonomous driving startis input. The period during which the manual driving state is maintainedis not limited to the period described above, and for example, thedriving state switching unit 16 may maintain the manual driving state ina period determined in advance. The input of the request operation ofautonomous driving start is not limited to the autonomous driving ON/OFFswitch 70, and known input means can be used.

As described above referring to FIG. 3 , a transition between theautonomous driving state and the cooperative driving state is determinedby comparing the intervention determination threshold value T₁ with thesteering torque based on the steering operation, and as indicated by anarrow in FIG. 3 , is a reversible transition. While a transition betweenthe cooperative driving state and the manual driving state is determinedby comparing the manual driving start threshold value T₂ with thesteering torque based on the steering operation, as indicated by anarrow in FIG. 3 , transition between the cooperative driving state andthe manual driving state is an irreversible transition where onlytransition from the cooperative driving state to the manual drivingstate is permitted. The driving state switching unit 16 outputsinformation relating to the driving state to the traveling control unit17.

The traveling control unit 17 allows the vehicle V to travel in thedriving state determined by the driving state switching unit 16. If thedriving state of the vehicle V is the autonomous driving state, thetraveling control unit 17 outputs a control signal to the actuator 6based on the traveling plan generated by the traveling plan generationunit 14, and controls traveling of the vehicle V. If the driving stateof the vehicle V is the cooperative driving state, the traveling controlunit 17 outputs a control signal to the actuator 6 based on thetraveling plan generated by the traveling plan generation unit 14 andsteering torque according to the steering operation acquired by thedriving operation information acquisition unit 15, and allows thevehicle V to travel in cooperation with the steering operation. If thedriving state of the vehicle V is the manual driving state, thetraveling control unit 17 outputs a control signal to the actuator 6based on steering torque according to the steering operation acquired bythe driving operation information acquisition unit 15, and reflectssteering torque according to the steering operation in traveling of thevehicle V. With this, the traveling control unit 17 realizes the threestates of the autonomous driving state, the cooperative driving state,and the manual driving state.

Next, processing which is performed by the autonomous driving vehiclesystem 100 will be described. FIG. 4 is a flowchart showing an exampleof traveling plan generation processing. Control processing shown inFIG. 4 is executed, for example, when the request operation ofautonomous driving start is input to the autonomous driving ON/OFFswitch 70.

As shown in FIG. 4 , first, the vehicle position recognition unit 11recognizes the vehicle position from the positional information of thevehicle V received by the GPS reception unit 2 and the map informationof the map database 4. The external situation recognition unit 12recognizes the external situation of the vehicle V from the detectionresult of the external sensor 1. The traveling state recognition unit 13recognizes the traveling state of the vehicle V from the detectionresult of the internal sensor 3 (S1). The traveling plan generation unit14 generates the traveling plan of the vehicle V from the target routeof the navigation system 5, the vehicle position, the external situationof the vehicle V, and the traveling state of the vehicle V (S2). In thisway, the traveling plan of the vehicle V is generated.

Next, switching processing of the driving state of the vehicle V whichis performed by the autonomous driving vehicle system 100 will bedescribed. FIG. 5 is a flowchart illustrating an example of switchingprocessing for switching the driving state of the vehicle V in themanual driving state using steering torque according to the steeringoperation. Control processing shown in FIG. 5 is repeatedly executed ata predetermined cycle when the vehicle V is in the manual driving state.

As shown in FIG. 5 , first, the driving state switching unit 16determines whether or not the request operation of autonomous drivingstart is input to the autonomous driving ON/OFF switch 70 when thedriving state of the vehicle V is the manual driving state (S10). Whenit is determined that the request operation of autonomous driving startis input to the autonomous driving ON/OFF switch 70, the driving stateswitching unit 16 performs determination processing (S12) using theintervention determination threshold value T₁.

The driving state switching unit 16 determines whether or not steeringtorque based on the detection result of the internal sensor 3 is lessthan the intervention determination threshold value T₁ as determinationprocessing using the intervention determination threshold value T₁ shownin S12. When it is determined that steering torque based on thedetection result of the internal sensor 3 is less than the interventiondetermination threshold value T₁, the driving state switching unit 16switches the driving state of the vehicle V to the autonomous drivingstate (S14). If the switching processing shown in S14 ends, theflowchart shown in FIG. 5 ends. The driving state of the vehicle Vtransitions from the manual driving state to the autonomous drivingstate, and is no longer in the manual driving state which is aprerequisite for the flowchart shown in FIG. 5 ; therefore, processingfor repeating the flowchart shown in FIG. 5 is not performedsubsequently, and a flowchart shown in FIG. 6 described below isstarted.

When it is determined that steering torque based on the detection resultof the internal sensor 3 is not less than the intervention determinationthreshold value T₁, the driving state switching unit 16 performsdetermination processing (S16) using the manual driving start thresholdvalue T₂. The driving state switching unit 16 determines whether or notsteering torque based on the detection result of the internal sensor 3is less than the manual driving start threshold value T₂ as thedetermination processing using the manual driving start threshold valueT₂ shown in S16. When it is determined that steering torque based on thedetection result of the internal sensor 3 is less than the manualdriving start threshold value T₂, the driving state switching unit 16switches the driving state of the vehicle V to the cooperative drivingstate (S18). If the switching processing shown in S18 ends, theflowchart shown in FIG. 5 ends. The driving state of the vehicle Vtransitions from the manual driving state to the cooperative drivingstate, and is no longer in the manual driving state which is aprerequisite for the flowchart shown in FIG. 5 ; therefore, processingfor repeating the flowchart shown in FIG. 5 is not performedsubsequently, and a flowchart shown in FIG. 6 described below isstarted.

When it is determined that steering torque based on the detection resultof the internal sensor 3 is not less than the manual driving startthreshold value T₂, the driving state switching unit 16 maintains themanual driving state (S20). Similarly, when it is determined that therequest operation of autonomous driving start is not input to theautonomous driving ON/OFF switch 70, the driving state switching unit 16maintains the manual driving state (S20). Then, the flowchart shown inFIG. 5 ends. Since the driving state does not transition out of themanual driving state, the flowchart shown in FIG. 5 is repeatedlyexecuted subsequently.

Next, switching processing of the driving state of the vehicle V whichis performed by the autonomous driving vehicle system 100 when thedriving state of the vehicle V is the autonomous driving state or thecooperative driving state will be described. FIG. 6 is a flowchartillustrating an example of switching processing for switching thedriving state of the vehicle V in the autonomous driving state or thecooperative driving state using steering torque. Control processingshown in FIG. 6 is repeatedly executed at a predetermined cycle when thevehicle V is in the autonomous driving state or the cooperative drivingstate.

As shown in FIG. 6 , first, the driving state switching unit 16determines whether or not steering torque based on the detection resultof the internal sensor 3 is less than the intervention determinationthreshold value T₁ as the determination processing using theintervention determination threshold value T₁ shown in S32. When it isdetermined that steering torque based on the detection result of theinternal sensor 3 is less than the intervention determination thresholdvalue T₁, the driving state switching unit 16 determines the drivingstate of the vehicle V to be the autonomous driving state (S34). Thatis, the driving state switching unit 16 maintains the autonomous drivingstate when the driving state of the vehicle V is the autonomous drivingstate, and switches the driving state to the autonomous driving statewhen the driving state of the vehicle V is the cooperative drivingstate. If the processing shown in S34 ends, the flowchart shown in FIG.6 ends. Since the driving state of the vehicle V does not transition tothe manual driving state, the flowchart shown in FIG. 6 is repeatedlyexecuted subsequently.

When it is determined that steering torque based on the detection resultof the internal sensor 3 is not less than the intervention determinationthreshold value T₁, the driving state switching unit 16 performs thedetermination processing (S36) using the manual driving start thresholdvalue T₂. The driving state switching unit 16 determines whether or notsteering torque based on the detection result of the internal sensor 3is less than the manual driving start threshold value T₂ as thedetermination processing using the manual driving start threshold valueT₂ shown in S36. When it is determined that steering torque based on thedetection result of the internal sensor 3 is less than the manualdriving start threshold value T₂, the driving state switching unit 16determines the driving state of the vehicle V to be the cooperativedriving state (S38). That is, the driving state switching unit 16switches the driving state to the cooperative driving state when thedriving state of the vehicle V is the autonomous driving state, andmaintains the cooperative driving state when the driving state of thevehicle V is the cooperative driving state. If the processing shown inS38 ends, the flowchart shown in FIG. 6 ends. Since the driving state ofthe vehicle V does not transition to the manual driving state, theflowchart shown in FIG. 6 is repeatedly executed subsequently.

When it is determined that steering torque based on the detection resultof the internal sensor 3 is not less than the manual driving startthreshold value T₂, the driving state switching unit 16 switches thedriving state to the manual driving state (S40). Then, the flowchartshown in FIG. 6 ends. The driving state of the vehicle V transition fromthe autonomous driving state or the cooperative driving state to themanual driving state, and is no longer in the autonomous driving stateor the cooperative driving state which is a prerequisite for theflowchart shown in FIG. 6 ; therefore, the flowchart shown in FIG. 6 isnot repeatedly performed subsequently, and the flowchart shown in FIG. 5is started.

As shown in FIGS. 5 and 6 , the autonomous driving state, thecooperative driving state, and the manual driving state are switchedbased on steering torque according to the steering operation by thedriving state switching unit 16. In FIGS. 5 and 6 , although a casewhere, when the driving state is the autonomous driving state and thecooperative driving state, the request operation of autonomous drivingend is input after the request operation of autonomous driving start isinput to the autonomous driving ON/OFF switch 70 is not shown, in thiscase, the driving state switching unit 16 performs processing forswitching from the autonomous driving state and the cooperative drivingstate to the manual driving state.

In the above description, although a case where the driving stateswitching unit 16 switches the driving state of the vehicle V based onthe operation amount (steering torque) of the steering operation as anexample of the driving operation has been described, steering torque maybe replaced with a steering angle, or may be replaced with thedepression amount (pedal position) of the accelerator pedal or the brakepedal. That is, the driving state switching unit 16 may switch thedriving state of the vehicle V based on the steering angle of thesteering operation, or may switch the driving state of the vehicle Vbased on the depression amount of the accelerator pedal or the brakepedal.

In the autonomous driving vehicle system 100 according to the firstembodiment, the driving state of the vehicle V is switched to one of theautonomous driving state, the manual driving state, and the cooperativedriving state based on the operation amount of the driving operation.For example, when an oncoming vehicle of a heavy vehicle type appearsduring traveling in the autonomous driving state, the driving state ofthe vehicle V is switched to the cooperative driving state by thedriving state switching unit 16 when the driver performs the drivingoperation such that the vehicle travels at a position slightly distancedfrom the heavy vehicle, and when the operation amount is equal to orgreater than the intervention determination threshold value T₁ and lessthan the manual driving start threshold value T₂. When the driver stopsthe driving operation after having passed the oncoming vehicle, thedriving state of the vehicle V is switched to the autonomous drivingstate by the driving state switching unit 16. For this reason, theautonomous driving vehicle system 100 can reduce a burden given to thedriver when the driver temporarily intervenes in the vehicle V in theautonomous driving state.

In the autonomous driving vehicle system 100 according to the firstembodiment, when the steering wheel of the vehicle V rotates accordingto the control target value of the steering wheel included in thetraveling plan, the driving operation information acquisition unit 15can acquire the difference between the rotation state detection value ofthe steering wheel of the vehicle V and the control target value of thesteering wheel included in the traveling plan as the operation amount ofthe steering operation. When the pedal position of the accelerator pedalof the vehicle V moves according to the control target value of theaccelerator pedal included in the traveling plan, the driving operationinformation acquisition unit 15 can acquire the difference between thepedal position detection value of the accelerator pedal of the vehicle Vand the control target value of the accelerator pedal included in thetraveling plan as the operation amount of the accelerator operation.When the pedal position of the brake pedal of the vehicle V movesaccording to the control target value of the brake pedal included in thetraveling plan, the driving operation information acquisition unit 15can acquire the difference between the pedal position detection value ofthe brake pedal of the vehicle V and the control target value of thebrake pedal included in the traveling plan as the operation amount ofthe brake operation. That is, even when the steering wheel rotatesaccording to the control target value or the pedal position of theaccelerator pedal or the brake pedal moves, the driving operationinformation acquisition unit 15 can acquire the operation amount of thedriver. In other words, even when the system operates the operating unitof the driver, the driving operation information acquisition unit 15 canacquire the operation amount of the driving operation of the driver tothe operating unit.

In the autonomous driving vehicle system 100 according to the firstembodiment, when the driving state of the vehicle V is the manualdriving state, the driving state switching unit 16 can maintain thedriving state in the manual driving state even when the operation amountis less than the manual driving start threshold value. The autonomousdriving vehicle system 100 does not perform switching to the autonomousdriving state when the driver performs the driving operation in asufficient operation amount with the intention of continuing the manualdriving state or the driving operation is sufficiently continued;therefore, it is possible to reduce a burden in switching the drivingstate given to the driver who desires to continue the manual drivingstate.

The autonomous driving vehicle system 100 according to the firstembodiment further includes the autonomous driving ON/OFF switch 70which is provided to input the request operation of autonomous drivingstart of the driver, and the driving state switching unit 16 canmaintain the driving state of the vehicle V in the manual driving stateuntil the request operation is input to the autonomous driving ON/OFFswitch 70 when the driving state of the vehicle V is the manual drivingstate. Accordingly, the autonomous driving vehicle system 100 does notperform switching to the autonomous driving state until there is arequest of autonomous driving start from the driver; therefore, it ispossible to reduce a burden in switching the driving state given to thedriver who desires to continue the manual driving state.

Second Embodiment

Next, an autonomous driving vehicle system according to a secondembodiment will be described. In the description of this embodiment,description of the same configuration and processing as in the firstembodiment will not be repeated, and the difference from the firstembodiment will be described.

The autonomous driving vehicle system according to this embodiment hasthe same configuration as the autonomous driving vehicle system 100according to the first embodiment, and only the functions of the drivingoperation information acquisition unit 15 and the driving stateswitching unit 16 of the ECU 10 are different.

The driving operation information acquisition unit 15 acquires aduration count according to a duration of the driving operation of thedriver relating to at least one of the steering operation, theaccelerator operation, and the brake operation of the vehicle V asdriving operation information. The duration of the driving operation isthe time when an operation amount equal to or greater than apredetermined threshold value is continued. For example, when thedriving operation of the driver is the steering operation, the durationof the steering operation is the time when the input of steering torqueequal to or greater than a predetermined threshold value is continued.For example, when the driving operation of the driver is the acceleratoroperation or the brake operation, the duration of the acceleratoroperation or the brake operation is the time when a pedal depressionamount equal to or greater than a predetermined threshold value iscontinued. The predetermined threshold value is a value set in advance,and a threshold value for determining the presence or absence ofoperation intervention of the driver. For example, as the predeterminedthreshold value, the intervention determination threshold value T₁described in the first embodiment may be used. Furthermore, thepredetermined threshold value is set for each of the steering operation,the accelerator operation, and the brake operation. The duration countis a value counted according to the duration of the driving operation.The duration count has a greater value, for example, as the duration ofthe driving operation increases. A method of calculating the durationcount will be described below. When the driving operation isinterrupted, a state where steering torque equal to or greater than thepredetermined threshold value is not input occurs. In this case, theduration count is reset. The driving operation information acquisitionunit 15 outputs the measured duration count to the driving stateswitching unit 16.

The driving state switching unit 16 switches the driving state of thevehicle V based on the duration count acquired by the driving operationinformation acquisition unit 15. Hereinafter, a case where the drivingstate switching unit 16 switches the driving state of the vehicle Vbased on the duration count of the steering operation as an example ofthe driving operation will be described.

FIGS. 7A to 7C are diagrams illustrating an example of the relationshipbetween the duration count according to the steering operation andtransition of the driving state of the vehicle V. The horizontal axisshown in FIG. 7A represents a duration count [sec], and the verticalaxis represents a driving state. As shown in FIG. 7A, the driving stateof the vehicle V includes three states of an autonomous driving state, acooperative driving state, and a manual driving state. The contents ofthe driving states are the same as those in the first embodiment.

The driving state switching unit 16 switches between the autonomousdriving state, the cooperative driving state, and the manual drivingstate based on the duration count according to the steering operation.When the duration count according to the steering operation is less thana first threshold value K₁, the driving state of the vehicle V becomesthe autonomous driving state. The first threshold value K₁ is a valueset in advance, and a threshold value which is used in order todetermine switching from the autonomous driving state to the cooperativedriving state. When the duration count according to the steeringoperation is equal to or greater than the first threshold value K₁ andless than a second threshold value K₂, the driving state of the vehicleV becomes the cooperative driving state. The second threshold value K₂is a value set in advance, and a threshold value for determiningswitching from the cooperative driving state to the manual drivingstate. When the duration count according to the steering operation isequal to or greater than the second threshold value K₂, the drivingstate of the vehicle V becomes the manual driving state.

Next, the determination (maintenance or transition) of the driving stateof the vehicle V will be described. First, the maintenance or transitionof the autonomous driving state will be described. The driving stateswitching unit 16 maintains the driving state of the vehicle V in theautonomous driving state when the driving state of the vehicle V is theautonomous driving state, and when the duration count according to thesteering operation is less than the first threshold value K₁. With this,for example, even when a driving operation not intending the release ofautonomous driving is detected, for example, even when the drivertouches the steering wheel unintentionally for a predetermined period,or the like, the autonomous driving state is not released. For thisreason, the driving state switching unit 16 can avoid the operation ofthe autonomous driving ON/OFF switch 70 by the driver in order toinstruct autonomous driving start each time the driver releasesautonomous driving unintentionally; therefore, it is possible to reducea burden given to the driver.

The driving state switching unit 16 switches the driving state of thevehicle V to the cooperative driving state when the driving state of thevehicle V is the autonomous driving state and when the duration countaccording to the steering operation is equal to or greater than thefirst threshold value K₁ and less than the second threshold value K₂.With this, for example, when the driver operates the steering wheel withthe duration count equal to or greater than the first threshold value K₁and less than the second threshold value K₂ in order to intervene in thevehicle V in the autonomous driving state, the driving state of thevehicle V transitions from the autonomous driving state to thecooperative driving state. For example, when an oncoming vehicle of aheavy vehicle type appears during traveling in the autonomous drivingstate, and when the driver performs the steering operation for apredetermined period such that the vehicle temporarily travels at aposition slightly distanced from the heavy vehicle, the driving state ofthe vehicle V is switched to the cooperative driving state by thedriving state switching unit 16. In this case, the vehicle V travelsbased on the steering operation amount of the driver in a state wheresystem intervention is possible; therefore, it is possible to allow thevehicle V to travel at a position based on the driving operation of thedriver.

The driving state switching unit 16 may switch the driving state of thevehicle V to the manual driving state when the driving state of thevehicle V is the autonomous driving state, and when the duration countaccording to the steering operation is equal to or greater than thesecond threshold value K₂. That is, the driving state of the vehicle Vmay transition directly from the autonomous driving state to the manualdriving state without passing through the cooperative driving state.

Next, the maintenance or transition of the cooperative driving statewill be described. The driving state switching unit 16 switches thedriving state of the vehicle V from the cooperative driving state to theautonomous driving state when the driving state of the vehicle V is thecooperative driving state, and when the duration count according to thesteering operation is less than the first threshold value K₁. With this,for example, when the driver performs the driving operation such thatthe vehicle travels at a position slightly distanced from a heavyvehicle as an oncoming vehicle and the driver stops the drivingoperation after having passed the oncoming vehicle, the driving state ofthe vehicle V is switched from the cooperative driving state to theautonomous driving state by the driving state switching unit 16. In thisway, when operation intervention is temporary, the driving state isautomatically switched to the autonomous driving state based on theduration count according to the steering operation. Therefore, since thedriving state switching unit 16 can avoid the operation of theautonomous driving ON/OFF switch 70 of the driver in order to instructautonomous driving start each time temporary autonomous driving isreleased, the driving state switching unit 16 can reduce a burden givento the driver.

The driving state switching unit 16 maintains the cooperative drivingstate when the driving state of the vehicle V is the cooperative drivingstate, and when the duration count according to the steering operationis maintained equal to or greater than the first threshold value K₁ andless than the second threshold value K₂. Then, the driving stateswitching unit 16 switches the driving state of the vehicle V from thecooperative driving state to the manual driving state when the drivingstate of the vehicle V is the cooperative driving state, and when theduration count according to the steering operation is equal to orgreater than the second threshold value K₂. With this, the operationamount of the steering operation of the driver is reflected in travelingof the vehicle V in a state where system intervention is not possible.

Next, the maintenance or transition of the manual driving state will bedescribed. The driving state switching unit 16 maintains the drivingstate in the manual driving state when the driving state of the vehicleV is the manual driving state, and when the duration count according tothe steering operation is less than the second threshold value K₂. Inthis case, when the driver performs the steering operation for a longperiod with the intention of continuing the manual driving state,switching to the autonomous driving state or the cooperative drivingstate is limited subsequently, for example switching to the autonomousdriving state or the cooperative driving state is prohibited orrestricted; therefore, it is possible to eliminate the need for thedriver to operate the autonomous driving ON/OFF switch 70 in order toinstruct autonomous driving end. For this reason, it is possible toreduce a burden given to the driver.

The driving state switching unit 16 maintains the manual driving stateuntil the request operation of autonomous driving start is input to theautonomous driving ON/OFF switch 70 when the driving state of thevehicle V is the manual driving state. That is, even when the durationcount according to the steering operation is less than the secondthreshold value K₂, transition to the cooperative driving state or theautonomous driving state is limited until the request operation ofautonomous driving start is input. The period during which the manualdriving state is continued is not limited thereto, and for example, thedriving state switching unit 16 may maintain manual driving for a perioddetermined in advance. The input of the request operation of autonomousdriving start is not limited to the autonomous driving ON/OFF switch 70,and known input means can be used.

As described above referring to FIG. 7A, transition between theautonomous driving state and the cooperative driving state is determinedby comparing the first threshold value K₁ with the duration count basedon the steering operation, and is a reversible transition. Whiletransition between the cooperative driving state and the manual drivingstate is determined by comparing the second threshold value K₂ with theduration count based on the steering operation, transition between thecooperative driving state and the manual driving state is anirreversible transition where only transition from the cooperativedriving state to the manual driving state is permitted.

Next, additional processing of the duration count according to thesteering operation will be described. The additional processing of theduration count according to the steering operation is processing using agenerally known increment function. For example, the driving stateswitching unit 16 performs increment processing for setting the initialvalue of the duration count according to the steering operation andadding the processing time of the CPU to the initial value or previousvalue of the duration count at each processing cycle of the CPU in theECU 10. The driving state switching unit 16 determines whether or notsteering torque equal to or greater than a predetermined threshold valueis input, and when steering torque is input, performs the additionalprocessing. The additional processing will be described referring toFIG. 7A. FIG. 7A shows a case where the additional processing isperformed in the autonomous driving state. An outlined point of FIG. 7A,represented by a circle, indicates the current duration count accordingto the steering operation at a given point in time. That is, in FIG. 7A,steering torque equal to or greater than a predetermined threshold valueis input, and the duration count according to the steering operation isincreased by the addition processing. When the duration count accordingto the steering operation is less than the first threshold value K₁, thedriving state of the vehicle V is maintained in the autonomous drivingstate, and when the duration count according to the steering operationis equal to or greater than the first threshold value K₁, the drivingstate of the vehicle V is switched from the autonomous driving state tothe cooperative driving state. In this way, the duration count accordingto the steering operation is increased by the additional processing, andthe driving state of the vehicle V is switched.

In regard to the increment processing, increment processing forintegrating a predetermined coefficient to the processing time of theCPU and adding the integrated value to the previous value of theduration count according to the steering operation may be performed.Furthermore, the predetermined coefficient may be a cumulative value ofsteering torque input by the driver equal to or greater than thepredetermined threshold value of the driver. In this case, an increaserate of the duration count according to the steering operation can beadjusted by the operation amount according to the steering operation;therefore, the driver can switch the driving state immediately to themanual driving state.

Next, processing of the duration count according to the steeringoperation when steering torque equal to or greater than thepredetermined threshold value is no longer input will be described. Whensteering torque equal to or greater than the predetermined thresholdvalue is no longer input, the driving state switching unit 16 resets theduration count according to the steering operation to 0. This processingwill be described referring to FIGS. 7B and 7C. FIG. 7B shows a casewhere steering torque equal to or greater than the predeterminedthreshold value is no longer input after the duration count shown inFIG. 7A. In this case, the duration count according to the steeringoperation is reset to 0, and the driving state is switched to theautonomous driving state. Thereafter, when steering torque equal to orgreater than the predetermined threshold value is input, as shown inFIG. 7C, the duration count is counted from 0.

The driving state switching unit 16 can reset the duration count to 0and can store the previous value of the duration count according to thesteering operation in a storage unit, for example, a memory, when thesteering operation is interrupted, and can set the stored previous valueas the initial value of the duration count according to the steeringoperation when the steering operation is resumed. That is, the drivingoperation information acquisition unit 15 can interrupt counting of theduration count according to the steering operation when the drivingoperation is interrupted. Alternatively, when the steering operation isinterrupted, the driving operation information acquisition unit 15 maystore the previous value of the duration count according to the steeringoperation in the storage unit, may subtract the previous value stored inthe storage unit according to the lapse of time, and may set thesubtracted previous value as the initial value of the duration countaccording to the steering operation. That is, the driving operationinformation acquisition unit 15 can change and set the initial value ofthe duration count. This setting processing can use a generally knowndecrement function. For example, decrement processing for subtractingthe processing time of the CPU from the previous value of the durationcount stored in the storage unit at each processing cycle of the CPU inthe ECU 10 is performed. When the previous value of the duration countis 0, the driving operation information acquisition unit 15 does notperform the decrement processing. The driving operation informationacquisition unit 15 may perform decrement processing for integrating apredetermined coefficient to the processing time of the CPU andsubtracting the integrated value from the previous value of the durationcount. With this configuration, it is possible to adjust a decrease rateof the initial value of the duration count.

FIGS. 8A to 8C are diagrams illustrating another example of therelationship between the duration count of the driving operation andtransition of the driving state of the vehicle V. The horizontal axisshown in FIG. 8A represents a duration count [sec], and the verticalaxis represents the driving state of the vehicle V. Similar to FIG. 7A,FIG. 8A shows a case where additional processing is performed in theautonomous driving state. FIG. 8B shows an initial value of a durationcount (initial duration count) stored in the storage unit when steeringtorque equal to or greater than a predetermined threshold value is notinput at the duration count shown in FIG. 8A. FIG. 8C shows a durationcount when steering torque equal to or greater than the predeterminedthreshold value is input after FIG. 8B. If steering torque equal to orgreater than the predetermined threshold value continues to be input, asshown in FIG. 8A, the duration count is incremented, and the drivingstate of the vehicle V is switched from the autonomous driving state tothe cooperative driving state. Thereafter, when steering torque equal toor greater than the predetermined threshold value is no longer input,the duration count is reset to 0, the driving state is switched to theautonomous driving state, and as shown in FIG. 8B, the initial durationcount to be the stored initial value is incremented. Thereafter, whensteering torque equal to or greater than the predetermined thresholdvalue is input, as shown in FIG. 8C, the subtracted previous value isset as an initial value, the increment of the duration count is resumed,and the driving state of the vehicle V is switched from the autonomousdriving state to the cooperative driving state. In this way, theduration count can be temporarily interrupted. After the duration countis reset, the increment processing is resumed using the previous value,and the duration count in which the intention of the driver to theprevious time is reflected can be used; therefore, it is possible toreduce the time until the driving state is switched to the manualdriving state compared to a case where the duration count is reset to 0.

Next, switching processing of the driving state of the vehicle V whichis performed by the autonomous driving vehicle system 100 will bedescribed. FIG. 9 is a flowchart illustrating an example of switchingprocessing for switching the driving state of the vehicle V in themanual driving state using the duration count of the steering operation.Control processing shown in FIG. 9 is repeatedly executed at apredetermined cycle when the vehicle V is in the manual driving state.

As shown in FIG. 9 , first, the driving state switching unit 16determines whether or not the request operation of autonomous drivingstart is input to the autonomous driving ON/OFF switch 70 when thedriving state of the vehicle V is the manual driving state (S44). Whenit is determined that the request operation of autonomous driving startis input to the autonomous driving ON/OFF switch 70, the driving stateswitching unit 16 performs determination processing (S46) using theintervention determination threshold value T₁.

The driving state switching unit 16 determines whether or not theoperation amount (steering torque) based on the detection result of theinternal sensor 3 is less than the intervention determination thresholdvalue T₁ as the determination processing using the interventiondetermination threshold value T₁ shown in S46. When it is determinedthat steering torque based on the detection result of the internalsensor 3 is not less than the intervention determination threshold valueT₁, the driving state switching unit 16 transitions to additionprocessing (S48) of the duration count.

The driving state switching unit 16 performs processing for increasingthe duration count of the steering operation as the addition processingshown in S48. Thereafter, the driving state switching unit 16 determineswhether or not the duration count of the steering operation is less thanthe first threshold value K₁ as determination processing using the firstthreshold value K₁ shown in S52. When it is determined that the durationcount of the steering operation is less than the first threshold valueK₁, the driving state switching unit 16 switches the driving state tothe autonomous driving state (S54). If the processing shown in S54 ends,the flowchart shown in FIG. 9 ends. The driving state of the vehicle Vtransitions from the manual driving state to the autonomous drivingstate, and is no longer in the manual driving state which is aprerequisite for the flowchart shown in FIG. 9 ; therefore, processingfor repeating the flowchart shown in FIG. 9 is not performedsubsequently, and a flowchart shown in FIG. 11 described below isstarted.

When it is determined that the duration count of the steering operationis not less than the first threshold value K₁, the driving stateswitching unit 16 performs determination processing (S56) using thesecond threshold value K₂. The driving state switching unit 16determines whether or not the duration count of the steering operationis less than the second threshold value K₂ as the determinationprocessing using the second threshold value K₂ shown in S56. When it isdetermined that the duration count of the steering operation is lessthan the second threshold value K₂, the driving state switching unit 16switches the driving state of the vehicle V to the cooperative drivingstate (S58). If the switching processing shown in S58 ends, theflowchart shown in FIG. 9 ends. The driving state of the vehicle Vtransitions from the manual driving state to the cooperative drivingstate, and is no longer in the manual driving state which is aprerequisite for the flowchart shown in FIG. 9 ; therefore, processingfor repeating the flowchart shown in FIG. 9 is not performedsubsequently, and the flowchart shown in FIG. 11 described below isstarted.

When it is determined that the duration count of the steering operationis not less than the second threshold value K₂, the driving stateswitching unit 16 maintains the manual driving state (S60). Similarly,when it is determined that the request operation of autonomous drivingstart is not input to the autonomous driving ON/OFF switch 70, thedriving state switching unit 16 maintains the manual driving state(S60). Then, the flowchart shown in FIG. 9 ends. Since the driving stateof the vehicle V does not transition out of the manual driving state,the flowchart shown in FIG. 9 is repeatedly executed subsequently.

In S46, when it is determined that steering torque based on thedetection result of the internal sensor 3 is less than the interventiondetermination threshold value T₁, the driving state switching unit 16transitions to initial value setting processing (S50). In the processingof S50, as the initial value of the duration count, 0, the storedprevious value, or the subtracted previous value is input.

Here, a case where the initial value of the duration count is changedwill be described in detail. FIG. 10 is a flowchart showing the initialvalue setting processing of S50. As shown in FIG. 10 , first, thedriving state switching unit 16 determines whether or not the currentduration count is 0 (S500). When it is determined that the durationcount is 0, the driving state switching unit 16 ends the flowchart shownin FIG. 10 . When it is determined that the duration count is not 0, thedriving state switching unit 16 performs read processing (S502) of theinitial duration count.

The driving state switching unit 16 reads the initial duration countstored in the storage unit as the read processing of the initialduration count shown in S502. When it is determined that steering torquebased on the detection result of the internal sensor 3 is less than theintervention determination threshold value T₁, the initial durationcount stored in the storage unit is updated by the driving stateswitching unit 16 with the duration count stored in the storage unit asthe initial value. Accordingly, the first time of the read processingshown in S502 becomes processing for reading, as the initial durationcount, the duration count when it is determined that steering torquebased on the detection result of the internal sensor 3 is less than theintervention determination threshold value T₁. Then, subsequent readprocessing which is continued until it is determined that steeringtorque based on the detection result of the internal sensor 3 is equalto or greater than the intervention determination threshold value T₁becomes read processing for reading the updated initial duration count(that is, the previous value of the initial duration count) as theinitial duration count. If the read processing of the initial durationcount is completed, the driving state switching unit 16 transitions tosubtraction processing (S504) of the initial duration count.

The driving state switching unit 16 decreases the initial duration countread by the processing of S502 as the subtraction processing of theinitial duration count shown in S504. If the subtraction processing ofthe initial duration count is completed, the driving state switchingunit 16 transitions to write processing (S506) of the initial durationcount.

The driving state switching unit 16 stores the initial duration countsubtracted by the processing of S504 in the storage unit as the writeprocessing of the initial duration count shown in S506. If the writeprocessing of the initial duration count is completed, the driving stateswitching unit 16 ends the flowchart shown in FIG. 10 .

As described above, the flowchart shown in FIG. 10 is executed, wherebythe initial duration count is stored and set as the initial value of theduration count at the time of return of the steering operation beinginterrupted.

Returning to the flowchart of FIG. 9 , if the processing of S50 ends,the driving state switching unit 16 switches the driving state of thevehicle V to the autonomous driving state (S54). Then, if the processingshown in S54 ends, the flowchart shown in FIG. 9 ends. The driving stateof the vehicle V transitions from the manual driving state to theautonomous driving state, and is no longer in the manual driving statewhich is a prerequisite for the flowchart shown in FIG. 9 ; therefore,processing for repeating the flowchart shown in FIG. 9 is not performedsubsequently, and the flowchart shown in FIG. 11 described below isstarted.

Next, switching processing of the driving state of the vehicle V whichis performed by the autonomous driving vehicle system 100 when thedriving state of the vehicle V is the autonomous driving state or thecooperative driving state will be described. FIG. 11 is a flowchartillustrating an example of switching processing for switching thedriving state of the vehicle V in the autonomous driving state or thecooperative driving state using the duration count of the drivingoperation. Control processing shown in FIG. 11 is repeatedly executed ata predetermined cycle when the vehicle V is in the autonomous drivingstate or the cooperative driving state.

As shown in FIG. 11 , first, the driving state switching unit 16determines whether or not an operation amount (torque) based on thedetection result of the internal sensor 3 is less than the interventiondetermination threshold value T₁ as determination processing using theintervention determination threshold value T₁ shown in S66. When it isdetermined that torque based on the detection result of the internalsensor 3 is not less than the intervention determination threshold valueT₁, the driving state switching unit 16 transitions to additionprocessing (S68) of the duration count.

The driving state switching unit 16 performs processing for increasingthe duration count as the addition processing shown in S68. Thereafter,the driving state switching unit 16 determines whether or not theduration count is less than the first threshold value K₁ asdetermination processing using the first threshold value K₁ shown inS72. When it is determined that the duration count is less than thefirst threshold value K₁, the driving state switching unit 16 determinesthe driving state of the vehicle V to be the autonomous driving state(S74). That is, the driving state switching unit 16 maintains theautonomous driving state when the driving state of the vehicle V is theautonomous driving state, and switches the driving state to theautonomous driving state when the driving state of the vehicle V is thecooperative driving state. If the processing shown in S74 ends, theflowchart shown in FIG. 11 ends. Since the driving state of the vehicleV does not transitions to the manual driving state, the flowchart shownin FIG. 11 is repeatedly executed subsequently.

When it is determined that the duration count is not less than the firstthreshold value K₁, the driving state switching unit 16 performsdetermination processing (S76) using the second threshold value K₂. Thedriving state switching unit 16 determines whether or not the durationcount is less than the second threshold value K₂ as the determinationprocessing using the second threshold value K₂ shown in S76. When it isdetermined that the duration count is less than the second thresholdvalue K₂, the driving state switching unit 16 determines the drivingstate of the vehicle V to be the cooperative driving state (S78). Thatis, the driving state switching unit 16 switches the driving state tothe cooperative driving state when the driving state of the vehicle V isthe autonomous driving state, and maintains the cooperative drivingstate when the driving state of the vehicle V is the cooperative drivingstate. If the processing shown in S78 ends, the flowchart shown in FIG.11 ends. Since the driving state does not transitions to the manualdriving state, the flowchart shown in FIG. 11 is repeatedly executedsubsequently.

When it is determined that the duration count is not less than thesecond threshold value K₂, the driving state switching unit 16 switchesthe driving state to the manual driving state (S80). Then, the flowchartshown in FIG. 11 ends. The driving state of the vehicle V transitionsfrom the autonomous driving state or the cooperative driving state tothe manual driving state, and is no longer in the autonomous drivingstate or the cooperative driving state which is a prerequisite for theflowchart shown in FIG. 11 ; therefore, processing for repeating theflowchart shown in FIG. 11 is not performed subsequently, and theflowchart shown in FIG. 9 is started.

In S66, when it is determined that steering torque based on thedetection result of the internal sensor 3 is less than the interventiondetermination threshold value T₁, the driving state switching unit 16transitions to initial value setting processing (S70). In the processingof S70, as the initial value of the duration count, 0, the storedprevious value, or the subtracted previous value is input. The initialvalue setting processing is the same as the processing of S50, and thus,description thereof will not be repeated.

As shown in FIGS. 9 to 11 , the autonomous driving state, thecooperative driving state, and the manual driving state are switchedbased on the duration count by the driving state switching unit 16. InFIGS. 9 and 11 , although a case where, when the driving state is theautonomous driving state or the cooperative driving state, the requestoperation of autonomous driving end is input after the request operationof autonomous driving start is input to the autonomous driving ON/OFFswitch 70 is not shown, in this case, the driving state switching unit16 performs processing for switching the driving state from theautonomous driving state or the cooperative driving state to the manualdriving state.

In the above description, although a case where the driving stateswitching unit 16 switches the driving state of the vehicle V based onthe duration count of the operation amount (steering torque) of thesteering operation as an example of the driving operation has beendescribed, steering torque may be replaced with a steering angle, or maybe replaced with the depression amount (pedal position) of theaccelerator pedal or the brake pedal. That is, the driving stateswitching unit 16 may switch the driving state of the vehicle V based onthe duration count of the steering angle of the steering operation, ormay switch the driving state of the vehicle V based on the depressionamount of the accelerator pedal or the brake pedal.

As described above, in the autonomous driving vehicle system 100according to the second embodiment, the driving state is switched to oneof the autonomous driving state, the manual driving state, and thecooperative driving state based on the duration count of the drivingoperation. For example, when an oncoming vehicle of a heavy vehicle typeappears during traveling in the autonomous driving state, and the driverperforms the driving operation such that the vehicle travels at aposition slightly distanced from the heavy vehicle, the driving state ofthe vehicle V is switched to the cooperative driving state by thedriving state switching unit 16 when the duration count is equal to orgreater than the first threshold value K₁ and less than the secondthreshold value K₂. Then, when the driver stops the driving operationafter having passed the oncoming vehicle, the driving state of thevehicle V is switched to the autonomous driving state by the drivingstate switching unit 16. For this reason, the autonomous driving vehiclesystem 100 can reduce a burden given to the driver when the drivertemporarily intervenes in the vehicle V in the autonomous driving state.

In the autonomous driving vehicle system 100 according to the secondembodiment, the duration count according to the duration is employed,whereby it is possible to realize transition to the manual driving statewithout inputting a great operation amount. For this reason, it ispossible to allow transition to the manual driving state withoutdisturbing the behavior of the vehicle.

Although some exemplary embodiments of the present disclosure have beendescribed, the invention is not limited to the embodiments describedabove. The invention can be carried out in various forms to whichvarious alterations and improvements are applied based on the knowledgeof a person skilled in the art, including the embodiments describedabove.

Modified Example 1

In the embodiments described above, although an example where thedriving state is switched based on one operation of the steeringoperation, the accelerator operation, and the brake operation has beendescribed, the driving state may be switched based on two or moreoperation amounts. FIGS. 12A and 12B are diagrams illustrating anexample of the relationship of the steering operation and the brakeoperation with transition of the driving state of the vehicle V. Thehorizontal axis shown in FIG. 12A represents steering torque [T], andthe vertical axis represents the driving state of the vehicle V. Thehorizontal axis shown in FIG. 12B represents a brake depression amount[deg], and the vertical axis represents the driving state of the vehicleV. Here, as shown in FIG. 12A, it is assumed that the detection value ofsteering torque is T_(S), and the detection value T_(S) is less than theintervention determination threshold value T₁. As shown in FIG. 12B, itis assumed that the detection value of the brake depression amount isT_(B), and the detection value T_(B) is equal to or greater than anintervention determination threshold value T₃ and less than a manualdriving start threshold value T₄. In this case, when determination isperformed by steering torque, the driving state is the autonomousdriving state, and when determination is performed by the brakedepression amount, the driving state becomes the cooperative drivingstate. In this way, the driving states of the vehicle V corresponding totwo or more operation amounts are different.

When the driving state of the vehicle V is the autonomous driving state,and when the driving state corresponding to steering torque is theautonomous driving state and the driving state corresponding to thebrake depression amount is the cooperative driving state, the drivingstate switching unit 16 switches the driving state of the vehicle V tothe cooperative driving state. Similarly, when the driving state of thevehicle V is the autonomous driving state, and when the driving statecorresponding to steering torque is the cooperative driving state andthe driving state corresponding to the brake depression amount is theautonomous driving state, the driving state switching unit 16 switchesthe driving state of the vehicle V to the cooperative driving state.When the driving state of the vehicle V is the cooperative drivingstate, and when the driving state corresponding to steering torque isthe autonomous driving state and the driving state corresponding to thebrake depression amount is the cooperative driving state, the drivingstate switching unit 16 maintains the driving state of the vehicle V inthe cooperative driving state. Similarly, when the driving state of thevehicle V is the cooperative driving state, and when the driving statecorresponding to steering torque is the cooperative driving state andthe driving state corresponding to the brake depression amount is theautonomous driving state, the driving state switching unit 16 maintainsthe driving state of the vehicle V in the cooperative driving state. Inthis way, switching to the cooperative driving state or the maintenanceof the cooperative driving state is given priority over the maintenanceof the autonomous driving state or switching to the autonomous drivingstate. That is, in the example of FIGS. 12A and 12B, the driving stateof the vehicle V becomes the cooperative driving state.

Additionally, when the driving state of the vehicle V is the cooperativedriving state, and when the driving state corresponding to steeringtorque is the cooperative driving state and the driving statecorresponding to the brake depression amount is the manual drivingstate, the driving state switching unit 16 switches the driving state ofthe vehicle V to the manual driving state. Similarly, when the drivingstate of the vehicle V is the cooperative driving state, and when thedriving state corresponding to steering torque is the manual drivingstate and the driving state corresponding to the brake depression amountis the cooperative driving state, the driving state switching unit 16switches the driving state of the vehicle V to the manual driving state.In this way, switching to the manual driving state is given priorityover the maintenance of the cooperative driving state.

According to the autonomous driving vehicle system of Modified Example1, when the driver performs a steering operation and an acceleratoroperation, it is possible to avoid switching to the autonomous drivingstate based on the release of the accelerator operation when the driverperforms a steering operation and a temporary accelerator operation withthe intention of switching to the manual driving state. That is, it ispossible to switch the driving state based on the driving operation inwhich the intention of the driver is most reflected. In Modified Example1 described above, although a case where the driving state is switchedusing the operation amount of the driving operation has been describedas an example, the invention can be applied to a case where the drivingstate is switched using the duration count of the driving operation, andthe same effects can be obtained.

Modified Example 2

In the embodiments described above, although a case where the samethreshold value is used as the threshold value for switching from theautonomous driving state to the cooperative driving state and thethreshold value for switching from the cooperative driving state to theautonomous driving state has been described, different threshold valuesmay be used. FIG. 13 is a diagram illustrating another example of therelationship between steering torque and transition of the driving stateof the vehicle V. As shown in FIG. 13 , the threshold value forswitching from the autonomous driving state to the cooperative drivingstate is referred to as T₁, and the threshold value for switching fromthe cooperative driving state to the autonomous driving state can be setto a threshold value T₀ (predetermined hysteresis threshold value)smaller than T₁. That is, after the driving state of the vehicle V isswitched from the autonomous driving state to the cooperative drivingstate, when the operation amount is less than the interventiondetermination threshold value T₁ but is equal to or greater than thethreshold value T₀, the driving state is maintained in the cooperativedriving state. In this case, it is possible to avoid frequent switchingof the state around the threshold value. Specifically, it is possible toavoid frequent switching of the driving state when the operation amountis substantially equal to the intervention determination threshold valueT₁. In Modified Example 2 described above, although a case where thedriving state is switched using the operation amount of the drivingoperation has been described as an example, the invention can be appliedto a case where the driving state is switched using the duration countof the driving operation, and the same effects can be obtained. In thiscase, after the driving state of the vehicle V is switched from theautonomous driving state to the cooperative driving state, when theduration count based on the operation amount becomes less than the firstthreshold value but is equal to or greater than a third threshold value,the driving state is maintained in the cooperative driving state. Thethird threshold value is a predetermined hysteresis duration thresholdvalue, and is a threshold value for switching from the cooperativedriving state to the autonomous driving state.

Modified Example 3

In the cooperative driving state of the embodiments described above,cooperative driving may be performed using a value obtained by weightingthe operation amount of the driver and the control target value based onthe traveling plan. With this setting, since it is possible to changethe degree of system intervention in the cooperative driving state, itis possible to perform transition of the driving state in considerationof vehicle behavior. For example, when a control target is steeringtorque, if steering torque of the driver is T_(D) and system inputtorque is T_(S), target steering torque T_(R) may be derived using thefollowing numerical expression.T _(R) =w ₁ ·T _(D) +w ₂ ·T _(S)  (1)where w₁ and w₂ are weights. The weights w₁ and w₂ may be constant orvariable. The weights w₁ and w₂ may be changed, for example, accordingto the speed of the vehicle V. FIG. 14 is a diagram illustrating anexample of a change of weighting in the cooperative driving state. InFIG. 14 , a threshold value T_(x) (determination threshold value) is setin a range greater than the intervention determination threshold valueT₁ and smaller than the manual driving start threshold value T₂, and theweights w₁ and w₂ in a section M1 of the threshold values T₁ to T_(x)are different from the weights w₁ and w₂ in a section M2 of thethreshold values T_(x) to T₂. The determination threshold value is athreshold value for changing weighting of a driver input and a systeminput in the cooperative driving state according to the operationamount. Here, in the section M1, the control target value based on thetraveling plan has a weight set to be greater than the operation amountof the driver (w₁<w₂), and in the section M2, the control target valuebased on the traveling plan has a weight set to be smaller than theoperation amount of the driver (w₁>w₂). In this way, the threshold valuemay be set to change weighting in the cooperative driving state. In FIG.14 , although an example where one threshold value is provided to changethe weights has been described, two or more threshold values may beprovided to change the weights.

Modified Example 4

In a further exemplary embodiment, the duration count of the drivingoperation may be calculated as a continuous duration including any ofthe steering operation, the accelerator operation, and the brakeoperation. For example, when the driver performs a steering operationand an accelerator operation in succession, the driving operationinformation acquisition unit 15 may acquire, as the duration count, aduration beginning from the start of the steering operation, which isequal to or greater than the predetermined threshold value set forth thesteering operation, continuing through to the accelerator operation,which is equal to or greater than the predetermined threshold value setfor the accelerator operation. That is, as long as one of the drivingoperations is continuously executed to a degree greater than or equal toits respective predetermined threshold value, the duration count may beextended.

What is claimed is:
 1. An autonomous driving apparatus for performingautonomous steering control of a vehicle and configured to switch adriving state of the vehicle, the apparatus comprising: a driving stateswitcher configured to, based on an operation amount of a steeringoperation of a driver, switch among a first state where the vehicletravels without the steering operation of the driver, a second statewhere the vehicle travels based on at least one of the steeringoperation of the driver and the autonomous steering control, and a thirdstate where the vehicle travels by manual steering operation of thedriver, wherein the driving state switcher is configured to: switch thedriving state to the second state when the driving state is the firststate, and the operation amount is equal to or greater than a firstthreshold value and less than a second threshold value, and switch thedriving state to the third state when the driving state is the secondstate, and the operation amount is equal to or greater than the secondthreshold value.
 2. The autonomous driving apparatus according to claim1, wherein a difference between a rotation state detection value of asteering wheel of the vehicle and a control target value of the steeringwheel is included in a traveling plan as the operation amount, whereinthe traveling plan is along a target route set in advance on a map by atraveling plan generator.
 3. The autonomous driving apparatus accordingto claim 1, wherein, when the driving state enters the third state, thedriving state switcher is configured to maintain the driving state inthe third driving state even when the operation amount becomes less thanthe second threshold value.
 4. The autonomous driving apparatusaccording to claim 3, wherein the driving state switcher is configuredto maintain the driving state in the third driving state until a requestoperation for starting autonomous driving is received when the drivingstate is the third driving state.
 5. The autonomous driving apparatusaccording to claim 1, wherein, after the driving state is switched fromthe first driving state to the second driving state, when the operationamount becomes less than the first threshold value and equal to orgreater than a predetermined hysteresis threshold value, the drivingstate switcher is configured to maintain the driving state in the seconddriving state.
 6. The autonomous driving apparatus according to claim 1,wherein, a control target value of a steering wheel is based on atraveling plan along a target route set in advance on a map by atraveling plan generator, and when the driving state is the seconddriving state, cooperative driving is performed using a value obtainedby weighting the operation amount and the control target value based onthe traveling plan, and a weight of weighting when the operation amountis equal to or greater than a determination threshold value is differentfrom the weight of weighting when the operation amount is less than thedetermination threshold value.
 7. The autonomous driving apparatusaccording to claim 1, wherein a control target value of a steering wheelis based on a traveling plan along a target route set in advance on amap by a traveling plan generator, and when the steering wheel of thevehicle rotates according to the control target value of the steeringwheel included in the traveling plan, a difference between a steeringtorque detection value of the steering wheel of the vehicle and asteering torque control target value included in the traveling plan isthe operation amount.
 8. The autonomous driving apparatus according toclaim 1, wherein when the driving state enters the third driving state,the driving state switching unit maintains the driving state in thethird driving state for a time period determined in advance.
 9. Theautonomous driving apparatus according to claim 1, wherein a durationcount is a time period during which the operation amount, which is equalto or greater than the first threshold value, is continued, and whereinthe driving state switcher is configured to switch the driving state tothe third state when the driving state is the first state, when theduration count is equal to or more than a time period set in advance.10. The autonomous driving apparatus according to claim 9, wherein whenthe driving operation is no longer equal to or greater than the firstthreshold value, the driving state switcher is configured to reset theduration count to 0 and switch the driving state to the first drivingstate.
 11. The autonomous driving apparatus according to claim 9,wherein when the driving operation is no longer equal to or greater thanthe first threshold value, the driving state switcher is configured tostore in a memory a previous value of the duration count, and set thestored previous value as an initial value of the duration count when thedriving operation is resumed.
 12. The autonomous driving apparatusaccording to claim 9, wherein when the driving operation is no longerequal to or greater than the first threshold value, the driving stateswitcher is configured to store in a memory a previous value of theduration count, subtract the previous value stored in the storage unitaccording to a lapse interval corresponding to an interruption of thedriving operation, and set the subtracted previous value as an initialvalue of the duration count when the driving operation is resumed. 13.The autonomous driving apparatus according to claim 1, wherein in thethird driving state, the operation amount is reflected in the travelingof the vehicle.
 14. The autonomous driving apparatus according to claim1, further comprising a Human Machine Interface (HMI) including anautonomous driving ON/OFF switch configured to input a request operationof starting autonomous driving.
 15. An autonomous driving apparatus forperforming autonomous steering control of a vehicle and configured toswitch a driving state of the vehicle, the apparatus comprising: a meansfor switching a driving state, based on an operation amount of asteering operation of a driver, among a first state where the vehicletravels without the steering operation of the driver, a second statewhere the vehicle travels based on at least one of the steeringoperation of the driver and the autonomous steering control, and a thirdstate where the vehicle travels by manual steering operation of thedriver, wherein, wherein the means for switching the driving state isconfigured to: switch the driving state to the second state when thedriving state is the first state, and the operation amount is equal toor greater than a first threshold value and less than the secondthreshold value, and switch the driving state to the third state whenthe driving state is the second state, and the operation amount is equalto or greater than the second threshold value.
 16. A method of switchinga driving state of a vehicle having autonomous driving vehicle control,the method comprising: switching a driving state, based on an operationamount of a steering operation of a driver, among a first state wherethe vehicle travels without the steering operation of the driver, asecond state where the vehicle travels based on at least one of thesteering operation of the driver and an autonomous steering control, anda third state where the vehicle travels by manual steering operation ofthe driver, wherein the switching the driving comprises: switching thedriving state to second state when the driving state is the first state,and the operation amount is equal to or greater than a first thresholdvalue and less than a second threshold value, and switching the drivingstate to the third state when the driving state is the second state, andthe operation amount is equal to or greater than the second thresholdvalue.